In fabricating a semiconductor device, various processing apparatuses (semiconductor apparatuses) are used to perform processings such as, for example, oxidation, diffusion, chemical vapor deposition (CVD), and annealing on a processing target object, for example, a substrate such as, for example, a semiconductor wafer (hereinafter, simply referred to as a “wafer”). In addition, as one of the processing apparatuses, a batch processing type heat treatment apparatus has been known in which a heat treatment may be performed on a plurality of wafers at one type.
In the batch processing type heat treatment apparatus, wafers are conveyed from the outside of the apparatus by a carrying container (also referred to as a “carrier” or a “FOUP”) configured to accommodate a plurality of wafers and the carrying container is supplied into the vertical heat treatment apparatus through, for example, a load port serving as a carry-in/out part of the apparatus. In addition, the wafers are taken out from the supplied carrying container and transferred to a boat (holder) configured to hold a plurality of wafers to be spaced apart from each other in a height direction. Subsequently, the boat is introduced into a heat treatment furnace having a furnace port in the lower end thereof from a lower side of the heat treatment furnace so that the wafers are provided to various processings.
In the vertical heat treatment apparatus, the furnace inlet of the heat treatment furnace is blocked by a cover provided below the boat while the boat is introduced into the heat treatment furnace. However, since the cover moves down together with the boat after the boat is taken out from the heat treatment furnace, the furnace inlet of the heat treatment furnace is in a released state.
When the furnace inlet is released, heat within the furnace is discharged to the outside of the heat treatment furnace, and thus, the temperature within furnace may decrease. Thus, when a heat treatment is performed on wafers of the next batch, a time is required for increasing the temperature, and as a result, the productivity may deteriorate. Further, the heat discharged from the inside of the furnace may have an adverse effect on components around the furnace inlet.
Therefore, for example, Japanese Patent Laid-Open Publication No. 04-147616 discloses a vertical heat treatment apparatus which is provided with a heat treatment furnace provided substantially vertically and including an opening for loading/unloading a processing target object in the lower end of the heat treatment furnace and an opening/closing mechanism configured to close the opening of the heat treatment furnace while no treatment is performed. In the vertical heat treatment apparatus disclosed in Japanese Patent Laid-Open Publication No. 04-147616, it is also disclosed that the opening/closing mechanism is constituted by, for example, a disc-shaped cover unit which is in contact with the circular opening of the heat treatment furnace, a drive mechanism unit for driving the cover unit, and an arm unit for connecting the cover unit and the drive mechanism unit.